If you are getting a blue light when the top cap is completely unscrewed from the body with the red wire still attached BUT getting a red/blue light when the cap is screwed back on, there's a short in the cap somewhere.
One way to check is to completely remove the top cap and check ohms from the top screw to the outside of the cap. Should read o.l. on the meter (open). If you're reading 0 or 1 ohms it's shorted somewhere.
Did you remove the clear tube shaped spacer and clean/check? It keeps the pin from touching the sides of the cap inside. I've had a short from liquid in there before.
One way to check is to completely remove the top cap and check ohms from the top screw to the outside of the cap. Should read o.l. on the meter (open). If you're reading 0 or 1 ohms it's shorted somewhere.
Did you remove the clear tube shaped spacer and clean/check? It keeps the pin from touching the sides of the cap inside. I've had a short from liquid in there before.